Regulation of rotary-converter electromotive force.



m. 692,02l. Patented Ian; 28, I902.

' .B. a. LAMME. REGULATION OF ROTARY CONVERTER.ELEGTROMOTIYE FORCE.

(Application filed Apr. 17, 1901.)

(No Model.)

- INVENTOR TORNEY.

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1 B. G. LAMME. REGULATION OF BOTARYGONVEBTER ELECTROIMII'I'IVE FORGE.

(Application filed Apr. 17, 1901.)

(No Model.) 2 Sheets-Sheet 2.

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UNITED STATES? ATENT' OFFicE;

BENJAMIN G. LAMME, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THEWESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORA- TION OFPENNSYLVANIA.

REGULATION OF ROTARY-CONVERTER ELECTROMOTIVE FORC E SPECIFICATIONforming part of Letters latent No. 692,021, dated January as, 1902.

Application filed April 17,1901.

To 00 whom it may concern:

Be it known that I, BENJAMIN G. LAMME, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented new and useful Improvements in Regulation ofRotary-Converter Eleotromotive Force, of which the following is aspecification.

My invention relates to apparatus employed for convertingalternating-current electrical energy into direct-current energy for theuse of translating devices; and it has for its object to provide acombinationand arrangement of apparatus'which shall-be. speciallyadaptedv for varying the direct-current electromotive force inaccordance with the load on the direct-currentcircuit.

My invention is illustrated in the accompanying drawings, in which- 7Figure 1 is a diagrammatic representation of apparatus suitable forpracticing the invention; and Fig. 2 is a side elevation of theapparatus shown diagrammatically inFig. 1. Fig. 3vis a diagrammaticrepresentation of a modification of my invention.

The rotary converter 1 has its armature 2, commutator drum 3, andcollector rings 4 mounted upon a shaft 5 in the usual manner, the shaftbeing journaled in suitable. bearings in pillars or standards 6, asuitable baseplate 7 being provided for these standards and thefield-magnet 8.

The field-magnet and field-magnet windings of the rotary converter maybe of any suitable character; but for convenience of auxiliaryregulation I have shown the fieldmagnet as provided with series coils 9and shunt-coils 10, the circuit of the latter having a rheostat 11includedvin it in order that the resistance of such circuit may bevaried in accordance with the electromotive-force regulation desired.

The rotary converter is combined with an induction-motor 12, thesecondary member 13 of which is shown as mounted upon the shaft 5; butit obviously might be otherwise coupled or geared to such shaft in ordertorotate therewith. The primary windings 14 of the motor 12 Serial No.56,331. (No model.)

are so arranged and connected as to provide magnetic poles that exceedin number those of the-rotary converter, so that the secondary member 13shall operate above normal synchronous speed. As here indicated, themotor has six poles and the rotary converter four poles, any othersuitable ratio being permissible, however.

The primary windings 14 of the motor have as many independent circuitsas there are supply-leads. In the present instance, the currents beingof three phases, there are three independent circuits and six leads a bc and a b 0 instead of three, as is usual with threephase windings.

If two-phase currents were employed, there would be four independentwindings on the motor and eight leads.

The leads a b c from the motor-windings 14: are so connected to therotary-converter armature-windings 15 by means of brushes 16 andcollector-rings 4 as to put the said windings in series with each other.Since the rotary converter is operated from an approximately constantpotential circuit, its speed and that of the motor Will be approximatelyconstant for all loads. Changes in load, however, call for correspondingchanges in the amount of energy supplied thereto by the rotaryconverter, and since the secondary member of the motor is mechanic- 8oally connected to the armature of the converter there is no variation inthe slip of the motor, and if it is operated above synchronous speed itreinforces the electromotiveforce component of the rotary-converterenergy in accordance with the changes in load on the converter, or,stated in another way, when an induction-motor is rotated either aboveor below synchronous speed any variation in the current input or outputmust be 0 caused by a variation in slip, or in voltage, or in both. Inthe present case there is no variation in the slip, and consequently allvariations in current are due to corresponding variations in voltage. Itfollows, therefore, 5 that as theload on the direct-current circuitvaries the current to supply the load Varies, and the current Variationsare in turn dependent,in whole orin part, upon voltage variations of themotor.

The compound winding of the field-magnet of the rotary converter mayalso be so adjusted and utilized as to effect an auxiliary adjustment ofthe electromotive force as the load comes on, as is set forth in PatentNo. 571,863, granted to R. D. Mershon, November 24, 1896, or in PatentNo. 620,343, granted to R. D. Mershon, February 28, 1899.

If the currents to the rotary converter are of such quality that aninconvenient winding would be required on the motor, the latter may besupplied from series-transformers, the secondaries of which areinterconnected in the usual star or delta manner for polyphase currents.With this arrangement the primary windings of the motor may be disposedand connected as is usual in polyphase induction-motors. I haveillustrated this modification in Fig. 3, in which conductors a b 0 thatsupply current to the rotary converter, are not connected to the motor,but have the primary windings 17, 18, and 19 of transformers 20, 21, and22, respectively, included therein. The secondaries of thesetransformers are connected to the primary windings 23 of the motor 12,which are here shown as arranged in star connection. Except as abovespecified, the modification shown in Fig. 3 has the same structureandmode of operation as the form of the invention shown in Figs. 1 and 2.

It will be understood that the result attained by mounting the secondarymember of the motor upon the armature-shaft of the rotary converter andproviding the primary member of the motor with windings that insure anumber of poles that exceeds the nu mber'of rotary-converterfield-magnet poles may be also attained by employing a motor having thesame or a less nu mber of poles than the rotary converter and connectingthe secondary member to the armature of the rotary con verter bysuitablespeed-changinggearing,so that the motor-secondary will be rotated abovesynchronous speed. It will be also understood that suit-able gearingmaybe employed between the motor-secondary' and the converterarmaturefor either reducing or increasing the speed of the former, whether thepoles of the two machines be equal or unequal in number, provided therelation between the number of motor-poles and the gearing is such as toinsure the desired degree of variation of the direct-currentelectromotive force.

My invention is not intended to be limited to specific types of machinesas regards windings, numbers of poles, or relative speeds of operation,except in so far as limitations may be imposed by the prior art andexpressed in the claims.

I claim as my invention- 1. The combination with a rotary converter andan induction-motor having a greater number of poles than the converter,of mechanical connections between the rotatable members of said machinesand means for supplying alternating currents to the said machines inseries.

2. The combination with a rotary converter and an induction-motor,having as many independent primary windings as there are phases ofcurrent and arranged to produce a number of magnetic poles that exceedsthe number of rotary-converter magnetic poles, of mechanical connectionsbetween the rotatable members of said machines and means for connectingthe primary windings of the motor in series with the armature-windingsof the rotary converter.

3. The combination with a rotary converter and an induction-motor;having a plurality of independent primary windings, the latter beingconnected and arranged to produce magnetic poles that exceed in numberthose of the converter, of mechanical connections between the armatureof the converter and the secondary member of the motor and means forsupplying polyphase alternating currents to the primary windings of themotor and armature-windings of the rotary converter in series.

4. The combination with a rotary converter, having a compound-woundfield-magnet of a given number of poles, of an induction-motor, havingits secondary member mechanically connected to the armature of therotary converter, and provided with a plurality of primary windingswhich are connected and arranged to produce magnetic poles that exceedin number those of the rotary converter, said motor primary windings androtary-converter armature-windings being connectedin series and suppliedwith polyphase alternating currents.

5. The combination with a rotary converter having a given number ofpoles, of an induction-motor mechanically connected thereto and having agreater number of poles, and means for connecting the armature-windingsof the converter and the primary windings of the motor in series witheach other.

6. The combination with a rotary converter and an induction-motor havingtheir rotata ble members mechanically connected together and means forsupplying polyphase currents to the primary member of the motor and tothe armature of the converter in series so as to produce magnetic polesin the motor,- the number of which exceeds the number of magnetic polesin the converter.

7. The combination with a rotary converter having a given number ofpoles and an induction-motor having a greater number of poles and havinga primary winding that is provided with twice as many leads as it haspolyphase circuits, of'mechanical connections between the rotatablemembers of the two machines and electrical connections between one-halfof said leads and the converter-armature.

8. The combination with a rotary converter and an induction-motor, ofmeans for connecting the primary windings of the motor and thearmature-windings of the converter {primary windings of the motor andthe armain series and mechanical connections between the secondarymember of the motor and the armature of the converter, the relationbetween the windings and mechanical connections being such as to insurerotation of the secondary member of the motor at other than synchronousspeed.

9. The combination with a polyphase induction-motor and a rotaryconverter having their rotatable members mechanically connectedtogether, of means for connecting the ture-windings of the converter inseries, the relation between the windings and mechanical connectionsbeing such that the motor operates at other than synchronous speed.

In testimony whereof I have hereunto subscribed my name this13th day ofApril; 1901.

BENJ. G. LAMME.

Witnesses:

WESLEY G. CARR, BIRNEY HINEs.

